STEAM NAVIGATION. 



therefore the weight of the engine is as much as 

 possible thrown below. For this purpose the work- 

 ing beam is taken away from the top, and in its stead 

 t\vo side levers are substituted, one on each side of 

 the engine, and each connected with the piston pump 

 rods and crank in a way which will at once be un- 

 derstood by inspecting the plates to which we shall 

 very soon refer. 



The revolving oars or paddle wheels having float 

 boards fastened upon their circumferences, are placed 

 at the sides of the vessel, and revolve upon the end 

 of the crankshaft, in the place of the fly wheel shown 

 in the plate of the condensing engine. Various 

 forms of these paddles have been tried, but upon 

 the whole it has been found that the common kind, 

 fashioned after the manner of an undershot water 

 wheel, answers best. From the nature of the re- 

 sistance which the engine has to encounter, the 

 paddles act as fly wheels, so that no fly wheel is re- 

 quired in a marine engine. 



By inspecting plate L XXXIV. the arrangement 

 of the several parts of a marine engine, as con- 

 structed by R. Napier, Esq. of Glasgow, will be 

 seen. This engine is similar in form to those made 

 by the celebrated engineer Maudsley of London. 

 The following account of a steam vessel lately 

 erected, but differing from the above in some of the 

 details, will render any farther description of this 

 plate unnecessary. 



References to plate LXXXV. of Steam Naviga- 

 tion ; A. Saloon. B.B. Gentlemen's state rooms. 

 C. Ladies' cabin. D.D. State rooms.. E.E. Wa- 

 ter closets FF. Wash hand basins G. Stewards' 

 pantry. H. Fore cabin. J. Ladies' fore cabin 

 K.K. Wash-hand basins. L. Main cabin stair 

 M. Fore cabin stair N. Engine room stair. 



1. Boiler 2. Funnel 3. Safety valve. 4. 



Cylinder 5. Side lever 6. Air pump 7. Con- 

 denser 9. Crank shaft 10. Cranks 11. Con- 

 necting rod 12. Paddle wheels. 13. Nozzle 



case 14. Bottom plates. 15. Foot valves 16. 



Discharging valves 17. Steam pipes 18. Ec- 

 centric rods 19. Parallel motion rods. 20. Cylin- 

 der side rods. 21. Diagonal stay and upper crank 

 framing 22. Transverse stay rods 23. Lower 

 crank-framing 24. Cylinder cross heads 25. Air 

 pump cross heads. 26. Cross tails. 27. Paddle 

 wheel shafts. 28. Upper chamber of condenser. 

 29. Lower chamber of condenser. 30. Pistons. 

 31. Piston rods 32. Main centres. 



Having given those references, we will now lay 

 before the reader a more detailed account of the 

 Sea Horse steamer. 



The Sea Horse steam ship was built by Thomas 

 Adamson, Esq., ship-builder, Dundee, and the en- 

 gines manufactured by Peter Borrie, Esq., Tay 

 Foundry, Dundee, who also fitted up and furnished 

 her cabins. This vessel is the largest ever built on 

 the Tay, having length of keel 150 feet, length on 

 deck 170 feet, breadth over the paddle boxes 48 

 feet, length of quarter deck 65 feet, and breadth 

 30 feet. The vessel is all timbered with oak of the 

 best quality, die square, and large scantling, being 

 thirteen inches at the keel, and made perfectly solid 

 and caulked outside and inside from stem to stern to 

 the six feet water line before the planking was put 

 on. The planking at the keel is six inches thick, 

 bolted horizontally through the keel, and at the 

 bilges it is seven inches thick, and also bolted edge 

 ways to each other, all strongly copper bolted 

 through and clenched inside. The keelson is oak, 

 fourteen inches by sixteen inches, bolted through 



with 1 inch copper in every floor timber, and 

 clenched on the under part of the keel. There are 

 four riders from stem to stern, fourteen inches square, 

 bolted in a similar manner to the keelson ; upon 

 these the engines and boilers rest. The vessel 

 throughout is planked with heavy planking, the 

 greater part amidship being six inches thick, bolted 

 edge ways to each other and through the vessel's 

 side. The lower side of the keel is covered from 

 end to end the whole breadth with iron plates 

 inch thick, bolted upwards, with the bolts counter 

 sunk in the plates. Her cubical displacement, when 

 immersed to the load water line, is about 800 tons ; 

 and allowing 420 tons for weight of vessel, engines, 

 boilers, equipments and stores, a dead weight of 

 380 tons can be transported by this vessel. Two 

 large fore and after holds are provided for the 

 stowage of this cargo, whose cubical capacity is 

 15,200 feet. 



The sole plates of the engines are strongly bolted 

 through the riders, thus rendering it impossible, 

 while the vessel holds together, that the engines 

 can sustain the least strain. The engines have no 

 connections with the deck beams. The two fram- 

 ings are securely bound together by horizontal 

 stays, which method is found superior in many re- 

 spects to the way formerly practised in binding the 

 engine framing to the deck beams. Besides other 

 advantages, it is found to do away, in a great mea- 

 sure, with that tremulous motion so universal and 

 so disagreeable on board of steam vessels. 



The space occupied by the engines and boilers is 

 fifty-four feet long by 23 feet broad by twelve feet 

 high. The boilers are twenty-eight feet long by 

 twenty-one feet broad by 9J feet high, having eight 

 furnaces, whose flues traverse the boilers twice, and 

 then the smoke passes into the funnel. Around the 

 funnel is the steam chest, from which a large pipe, 

 with two verticle branches at the opposite end, 

 communicates to the nozle casing, and the steam 

 is admitted to and educted from the cylinders by 

 slide valves wrought from the paddle shaft by ec- 

 centrics in the usual manner. The relative situa- 

 tion of the boilers and engines are different from 

 the common method. Instead of the cylinders be- 

 ing next the boilers, they are placed at the opposite 

 end of the sole plates. Thus the cylinders are a- 

 head of the paddle shaft instead of being a-stern. 

 From this arrangement several advantages result, 

 the principal of which is, that the shaft is placed 

 nearer the centre of buoyancy, which causes the 

 paddle floats to operate with much better effect on 

 the water, and gives an increased speed to the ves- 

 sel. 



One of the greatest difficulties encountered in 

 applying steam to the purposes of navigation, arises 

 from the necessity of having to supply the boiler 

 with sea water. This cannot be avoided where 

 the common condenser is used and the condensation 

 of the steam effected by a jet of sea water, as the 

 boiler is supplied from the condenser, and this water 

 holds in solution a proportional quantity of salt to 

 the quantity of water used. 



The salt, thus conveyed into the boiler, not being 

 evaporated, remains there; and as a constant egression 

 of steam from the boiler causes as regular an increase 

 of salt, its accumulation soon becomes greater than 

 what water is capable of holding in solution ; a de- 

 position of salt in the boilers immediately com- 

 mences, which in process of time would fill them. 

 And. in addition to the salt thus conveyed into 

 the boilers, under some circumstances a deposition 



